An adhesive tape is used as a reliable adhesive joint member having excellent workability to fix members therebetween, temporarily fix members therebeween, label product information, or the like, in industrial fields such as office automation equipment, IT—home electric appliances, or automobiles. In recent years, the demand for recycling and reusing used products has increased in various industrial fields such as home electrical appliances or automobiles from the standpoint of protection of the earth's environment. In the case where various products are recycled or reused, although adhesive tapes used to fix members or as labels are required to be peeled therefrom, the adhesive tapes are used on various positions in the products, and therefore a decrease in the operation cost by performing a simple removing process is demanded.
As an easily dismantlable adhesive tape, an adhesive member having at least two adhesive layers, the adhesive strengths of which are different from each other, is disclosed, for example (see Patent Document 1). The adhesive tape is an adhesive member which realizes both strong fixation of an adherend and easy dismantling at a weakly-adhesive layer serving as the separation surface by joining the adherend via the weakly-adhesive layer of the adhesive member including adhesive layers with a superposed structure. However, the adhesive member has a problem in that the production cost thereof increases, because plural adhesive layers are essential components thereof. In addition, since the structure of the adhesive member allows bonding with an adherend via the weakly-adhesive layer, there is a limitation on an increase in the adhesive strength thereof, and it is difficult for the adhesive member to be used to strongly fix members. In particular, the adhesive properties may be decreased under low temperature conditions. Due to this, it is desirable to achieve dismantling while maintaining stable adhesive strength under ordinary temperature or lower temperature conditions.
As another easily dismantlable adhesive composition, an adhesive composition containing an aliphatic polyester is disclosed (see Patent Document 2). The adhesive composition is disclosed to be easily delaminable due to hydrolysis-promoting action of polycaprolactone when immersed in hot water in a peeling process. However, since the adhesive composition requires to be immersed in hot water when peeling is performed, the equipment cost is high when the adhesive composition is applied to a part having a large size to be dismantlable, and the adhesive composition cannot be applied to parts to which water cannot be applied when reused, such as electronic parts.
An adhesive composition containing a block copolymer obtained by preparing an acrylic copolymer having a carboxyl precursor group (—COOt-butyl) in an acrylic polymer block and then converting the carboxyl precursor group to a carboxyl group is disclosed as an adhesive composition using an acrylic block copolymer (see Patent Document 3). Although the adhesive composition is obtained by preparing an acrylic copolymer having a t-butyl group in a side chain thereof as a carboxyl precursor group, the t-butyl group does not remain in the obtained adhesive composition, and no dismantling properties are exhibited.